Randy  Dahlgren

A research project sponsored by the Integrated Hardwood Range Management Program examining nutrient cycling is showing that oak trees play a major role in maintaining the nutrient status of these ecosystems. Each year, a typical blue oak (Quercus douglasii) will return approximately 2, 1, 2.5, and 1.8 kg of nitrogen, phosphorus, calcium and potassium, respectively, to the soil surface in the form of litterfall (leaves, twigs and acorns) and canopy throughfall (canopy leaching).